Piling is a common land reclamation technology and foundation practice to direct heavy load of a structure to solid soil, for example to bedrock. Nowadays in piling is most often used steel concrete or steel pipe piles, which stands better than for example wood hits form piling machines and conserve as rot-proof in the ground.
Amount of needed piles in a building site depends naturally on area of the building to be constructed. In bridge or road construction sites are needed approximately 300 piles. For example in a middle size flat building site are needed approximately 150 piles to pile the groundwork. Length of a single concrete pile is 3-15 meters, and if a need arises it can be lengthened. In the end of the piling work the pile standing in ground surface has to be cut to have suitable length in order to continue with other construction site works.
Cutting of the pile is operated as separate work process in the construction site, and the cutting is commonly performed by a separate cutting unit, which is ordered to construction sites in order to cut the piles. Cutting of a pile is physically very demanding work, which comprises manual work phases. In method according to the state of the art cutting of the piles is usually performed by first digging enough ground around the piles so that it is possible to measure cutting height of the piles in order to perform the cutting work of the piles in the next work phase. The cutting is performed by sawing and by wedging them in two, and then an excavator collects upper parts of the piles to carry them away from the construction site. After this ground surface is underdrained and ballasted for upcoming forming of foundry.
Because the piles are usually cut in amount of 30-80 piles, the cutting work phases have to performed for example 7-10 times in construction site of 300 piles, which takes time and is expensive, because meanwhile other works can not be performed before cutting work phases have been finalized. Both a measure man and pile cutter have to perform their work in watery and sinking excavation, that has certain work safety problems.
It could be possible to perform underdraining and ballasting before cutting of the piles to make work safety better, but then the cutting level is too near (usually about 5 cm) ballast surface, which makes cutting more difficult or even impossible, because prior art cutting of piles requires about 10 cm of cutting level from the ground surface. There are often also piles to be cut near excavators or so high that it is in practice impossible to perform cutting of piles. It can also be impossible to perform cutting of piles due to too watery, slippery and/or sinking excavators or due to less than 10 cm cutting level.
After sawing the final breaking of piles in two parts is performed according to the prior art by a wedge and by a sledgehammer. This work phase is physically demanding and requires separate tools.
In patent document FI122291 is presented one example of prior art cutting devices, which are connected to a working machine for cutting of piles. On the basis of preliminary search examinations this document clearly represents the closest prior art to the present invention. In document FI122291 is presented a cutting device, in which sawing means have been fixed to gripping means in order to move the sawing means longitudinally towards the gripping means. Patent document FI122291 does not present any embodiment to compensate extensions and forces, which the sawing means have to receive during sawing. The prior art drawback of said document is that sawing means suffer by loosing their sharpness substantially fast or even by breaking down.